A mod’s script failed while the game was running, and the game stopped. The game names the mod. Turn that mod off, or update it, then start the server.
Find the mod
- Open Crashes.
- In the list of starts on the left, open the start marked Crashed.
- Under What the panel can tell, find A mod crashed the server. When the game names the mod, the title reads “The mod (name) (version) crashed the server”.
The panel explains: “The game names the mod and what it was doing. Turn that mod off on the Mods page (or update it), then start the server; tell the mod’s author with the lines below.”
The log lines look like this:
The mod example-mod (1.0.0) caused a non-recoverable error.
Quitting: multiplayer error.The first line has the mod’s name and its version, and usually the file and line of the error below it. Keep these lines. They are what the mod’s author needs.
Turn the mod off
- Open the Mods page.
- Find the mod. Wube’s own mods are listed under Wube’s own, where they are turned on or off.
- If its row menu More for (name) offers Update to (version), choose it first. The author may have fixed it. Updating needs the server’s factorio.com account: the username on Startup and the token under Passwords.
- Otherwise use the switch Turn (name) off on the row. The panel says: “Turned off. It stays on the server and is skipped from the next start.”
- A save that used this mod may lose what the mod added. Choose Save a copy now on the World page first.
- Start the server. If it is still running, use Restart, which drops everyone who is on. Warn them first with Message everyone on the Players page.
Turning a mod off applies at the next start. The mod stays on the server, so you can turn it on again later. Choose Remove from the row menu only when you want it gone. Its settings stay in case it comes back.
If other mods need the one you turn off, they may fail to load. The server then shows A mod could not load, so the server did not start. Turn those off too, or see a mod could not load.
Tell the players
Everyone who joins needs the same mods as the server. After you turn a mod off, players who still have it on may be refused or sent back to rejoin.
Tell the author
Copy the lines under the finding and send them to the mod’s author. Say which Factorio version you run. The Game version of that start is on the Crashes page.
Get the world back
The server stopped on an error, so it may not have saved last. The server runs the save named under World, and autosaves are separate files, so after a crash that save can be older than the newest autosave. Open World, compare the times under Saves, and on the autosave you want open More for (name) and choose Run this from the next start. See reading the Crashes page.
If it does not work
- It crashes again with a different mod named. Turn that one off too. Each crash names one mod.
- The crash names no mod. It is a different kind of failure. See the Crashes page.
- The server still will not start. Turn off the last mod you added and start again.
- You cannot find the mod in the list. It may be one of Wube’s own. Look under Wube’s own.
Not checked on 2.1.24 as of 13 November 2026: a mod crash with real players on a Loafhosts server. The behaviour above was measured with test mods.
More about the game: Factorio servers.
Sources: wiki.factorio.com: Multiplayer